Soil pH — Benchmark Detail

Benchmark Value

No specific value — see range

Range: 5.5 to 6 pH

Optimal Range: 5.5 to 6

Direction: Higher is desirable ↑

Form: OptimalRange

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context. The scoring engine uses 10 benchmarks together — the OptimalRange form drives the primary score, while 9 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary OptimalRange Guard LowerThreshold Guard UpperThreshold Guard OptimalRange Guard OptimalRange Guard LowerThreshold Guard OptimalRange Guard UpperThreshold Guard UpperThreshold Guard

Evidence & Context

Therefore, a reference range of pH(CaCl₂) 5.5 – 6.0 is proposed.

Metric Definition:

Soil pH measured in 0.01M calcium chloride solution (pH(CaCl₂)) representing the acidity/alkalinity of soil relevant to agricultural crop production.

Benchmark Definition:

This benchmark defines the optimal soil pH range for sustainable cropping in Australian Temperate Dry Woodlands & Native Grasslands, balancing nutrient availability and soil ecological health.

Justification:

The benchmark is derived by synthesizing native ecosystem soil pH data and sustainable agricultural guidelines, representing a balance between ameliorating natural soil acidity and maintaining soil ecological health.

Sources (2)

Preview of McIntyre, S., Stol, J., Harvey, J., Nicholls, A.O., Campbell, M., Reid, A., Manning, A.D. & Lindenmayer, D. (2010). Biomass and floristic patterns in the ground layer vegetation of box-gum grassy eucalypt woodland in Goorooyarroo and Mulligans Flat Nature Reserves, Australian Capital Territory. Cunninghamia 11(3): 319–357.

McIntyre, S., Stol, J., Harvey, J., Nicholls, A.O., Campbell, M., Reid, A., Manning, A.D. & Lindenmayer, D. (2010). Biomass and floristic patterns in the ground layer vegetation of box-gum grassy eucalypt woodland in Goorooyarroo and Mulligans Flat Nature Reserves, Australian Capital Territory. Cunninghamia 11(3): 319–357. Journal

View Source

Preview of SECTION 5 Wheat - Nutrition and fertiliser - GRDC, accessed July 8, 2025

SECTION 5 Wheat - Nutrition and fertiliser - GRDC, accessed July 8, 2025 Journal

Grains Research and Development Corporation (GRDC). (2016). GrowNote Wheat South 05 Nutrition.

View Source

Context

Region Australia
Biome Temperate Dry Woodlands & Native Grasslands
Land Use Agricultural Crop Production
Assessment Pristine Reference
Evidence Type TargetCondition

Lifecycle

Status Superseded
Version 1
Effective From 25 Mar 2026
Effective To 25 Mar 2026

Notes

Lower Critical Threshold: pH(CaCl₂) <4.7 increases risks of Al/Mn toxicity and compromises microbial health. Optimal Range: 5.5-6.5 supports nutrient availability and microbial activity. Upper Detrimental Threshold: Not definitively established, but caution advised above pH 7.0 due to potential nutrient imbalances and ecosystem impacts.

Related Benchmarks

Other benchmarks in the AUS-TDG-AGR-SPH family.